Star Trek : The Next Generation - Time's Arrow
An engineering team finds evidence of an alien presence on Earth in 19th century San Francisco: Data's severed head, buried five hundred years ago. An investigation inadvertently sends Data back to 19th century San Francisco, where he meets Jack London, Mark Twain, and a younger version of the long lived Guinan. Following Data back in time the crew of the Enterprise must locate Data and prevent his death while stopping the eni...